/*
 * Find expanded AES keys in memory 
 * 
 * Algorithm discovered and developed by Victor Muñoz
 *  - PoC and source published at 24c3 at December 2007
 * 
 * Thanks for the great moments and code snippets!
 *
 * This source is public domain. Feel free to use it and distribute it.
 */

#include <r_search.h>

const ut8 table_sbox[256] = {
	0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
	0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
	0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
	0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
	0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
	0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
	0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
	0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
	0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
	0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
	0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
	0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
	0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
	0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
	0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
	0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16
};

static bool aes256_key_test(const unsigned char *buf) {
	return (buf[32] == (buf[0] ^ table_sbox[buf[29]] ^ 1) \
		&& buf[33] == (buf[1] ^ table_sbox[buf[30]]) \
		&& buf[34] == (buf[2] ^ table_sbox[buf[31]]) \
		&& buf[35] == (buf[3] ^ table_sbox[buf[28]]));
}

static bool aes192_key_test(const unsigned char *buf) {
	return (buf[24] == (buf[0] ^ table_sbox[buf[21]] ^ 1) \
		&& buf[25] == (buf[1] ^ table_sbox[buf[22]]) \
		&& buf[26] == (buf[2] ^ table_sbox[buf[23]]) \
		&& buf[27] == (buf[3] ^ table_sbox[buf[20]]));
}

static bool aes128_key_test(const unsigned char *buf) {
	return (buf[16] == (buf[0] ^ table_sbox[buf[13]] ^ 1) \
		&& buf[17] == (buf[1] ^ table_sbox[buf[14]]) \
		&& buf[18] == (buf[2] ^ table_sbox[buf[15]]) \
		&& buf[19] == (buf[3] ^ table_sbox[buf[12]]));
}

R_API int r_search_aes_update(RSearch *s, ut64 from, const ut8 *buf, int len) {
	int i, last = len - 20;
	RListIter *iter;
	RSearchKeyword *kw;

	r_list_foreach (s->kws, iter, kw) {
		if (last > 0) {
			for (i = 0; i < last; i++) {
				if (aes128_key_test (buf + i)) {
					kw->keyword_length = 16;
					return r_search_hit_new (s, kw, from + i);
				}
				if (len - i - 28 > 0) {
					if (aes192_key_test (buf + i)) {
						kw->keyword_length = 24;
						return r_search_hit_new (s, kw, from + i);
					}
				}
				if (len - i - 36 > 0) {
					if (aes256_key_test (buf + i)) {
						kw->keyword_length = 32;
						return r_search_hit_new (s, kw, from + i);
					}
				}
			}
		}
	}
	return 0;
}
